This invention relates generally to liquid heating systems, and more particularly to an improved heating system for swimming pools which prevents pool water flow through the heat exchanger when not in use.
Swimming pool heating devices installed within the pool water filtering arrangement have become more popular as have swimming pools themselves. One form of pool water heating incorporates a solar heating panel, typically placed atop the roof of the home.
In-line heating elements have also become more widely used. These heating elements are typically in the form of either a heat exchanger or a natural gas or propane heating element, both of which incorporate a through flow heat exchange coils.
Because pool water typically includes a small level of chlorine, continuous flow of the pool water through the heat exchanger, even when not in use, tends to reduce the life of the heat exchange coils. Additionally, these heat exchangers have a peak operating efficiency which is specified by water flow rate and/or water temperature rise across the coils.
The invention to Johnson in U.S. Pat. No. 3,786,921 is directed to an arrangement which at least partially shunts water flow through the heater coil to regulate the heating efficiency of this system.
In Leniger U.S. Pat. No. 4,279,128, a swimming pool heater is disclosed including a system bypass line, which, in conjunction with a diverter valve, diverts a portion of the circulated pool water to the pool heater.
Neither of these above systems provide for the total intermittent discontinuance of pool water flow through the heat exchanger, however.
Applicant is also aware of the flow control arrangements for solar pool heaters as disclosed in Stewart U.S. Pat. Nos. 4,261,332 and 4,307,707, and Trihey U.S. Pat. No. 4,313,421.
The present invention provides an improved water flow arrangement for swimming pool filtering systems having a heat exchanger wherein water flow through the heat exchanger is totally interrupted at predetermined pool outlet water temperatures. Additionally, flow through the heat exchanger is adjustably controllable to optimize efficiency of the heat exchanger when in use.